Memory devices are typically provided as internal, semiconductor, integrated circuits and/or external removable devices in computers, personal digital assistants (PDAs), digital cameras, and cellular telephones, among various other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), phase change random access memory (PCRAM), and flash memory, among others.
Flash memory devices are utilized as non-volatile memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption.
Various types of memory can be used in memory systems. The various types of memory can be used in any combination to provide memory for a host device. For example, Flash memory can be included in a memory system. Flash memory can be part of a memory system as internal memory or as removable memory that can be coupled to the memory system through an interface, such as a USB connection.
A memory system can include a host device, host system memory, and a number of external memory devices. The host device can have a number of processors, a host controller, host controller memory that is located on the host controller, and a number of internal memory devices. The host device can use the internal and/or the external memory devices by interacting with the memory devices via a host controller. The host controller can communicate with the memory devices to perform operations on the memory devices, such as reading data from the memory devices to the host system or writing data from the host system to the memory devices. The commands that control the reading and writing of data can be built by the host system. The host controller can have hardware that controls the memory device capabilities in the commands. In such cases when a host controller has hardware that defines the memory devices capabilities, the host controller is limited to building commands that have the capabilities associated with the hardware that is on the host controller.